System of deicing for aircraft, vessels, etc.



Jan. 27,-1948. w. c. HASSELHO RN SYSTEM OF DEICING FOR AIRCRAFT,VESSELS,

ETC. 4

2 Sheets-Sheet'l Filed Dec. 6, 1943 R m n u p E U P a m R P m m w 3 1 f0WINDSHIELD I INVENTOR. walk? 6 flasselfwrnr,

"Hill H w. c. HASSELHORN Filed Dec. 6, 1943 INF- H H SYSTEM DEICING FORAIRCRAFT, VESSELS, ETC.

Jan. 27, 1948.

, INVENTOR. ZZ/allfer flfihsielfiam. 60 61 Patented Jan. 27, 1948 SYSTEMOF DEICING FOR AIRCRAFT, VESSELS, ETC.

Walter C. Hasselhorn, Chicago, Ill., assignor to Cook Electric Company,Chicago, 111., a corporation of Illinois Application December 6, 1943,Serial No. 512,999

18 Claims. (Cl. 244-134) This invention relates to de-icing systemsadapted particularly to the delivery of a deicing solution to variouslocations on aircraft, vessels or wherever the prevention of ice orfrost formation is desirable.

An object of the invention is to provide a deicing system embodyingcertain novel features both in construction and operation that providesnew and useful results in a device of this type. Among other things maybe mentioned the low power consumption and the efficient operation ofthe system to maintain a steady supply of a de-icing solution to one ormore locations and to measure the fluid so supplied. Although the broadconcept of the invention is not limited in application to the kind ofpower used, in its narrower aspects the invention novelly provides anelectric control circuit for the pumping units employed. The pumpingunits may also be electrically operated when desired and the currentimpulses of the control circuit used to control the operation of thepumping units. A further novel feature of the invention resides in theactuator employed. This actuator may be designed to operate the pumpingunits intermittently, which effects energization of the various unitsbut deenergizes each unit before energizing the next unit. A powercut-off is operated by the actuator so that the feed is limited to thestroke of each pump. In this manner, the over-heating of the pumpingunits and an unnecessary drain on the battery are prevented.

More specifically, this novel type of control circuit embodies certaincontrol characteristics particularly adapting the circuit to the controlof this system disclosed. These control characteristics includecontrolling the duration and frequency of the current impulses producedby the circuit so that the actuator may be made to operate a pumpingunit for each current impulse, the pumping unit remaining operated onlyfor the period of the impulses and the time interval between theseimpulses controlling the interval between operations of these pumpingunits. Thus, a selector device that can readily be adjusted to vary thetime interval between current impulses, may be used to control the rateof supply of each pumping unit. Although it is not necessary, the periodor duration of each current impulse may be limited so that a relayoperating the actuator can remain energized only long enough to alloweach pumping unit as it operates to make a full stroke.

Other objects and advantages of the invention will be apparent from thefollowing description when taken in connection with the accompanyingdrawings, which form a part hereof:

In the drawings:

Figure 1 is a diagrammatic layout of a deicing system embodying theinvention;

Fig. 2 is a wiring diagram of the same;

Fig. 3 is a longitudinalsectional view of one of the pumping units.

Fig. 4 is a top view of the actuator; and

Fig. 5 is a side view of the actuator.

Referring to the drawings, the de-icing system herein disclosed includesa control panel I, which may be located in the operators compartment, anelectronic timer 2, a source of de-icing solution 3 and a series ofpumping units 4, 5 and 6 discharging their output to a number oflocations, which, if an airplane, may comprise the propellers,carburetors, Windshields, wings, etc. It will be understood at theoutset that the number of pumping units may vary and that more than onepumping unit may be used to supply a single location. These pumpingunits as well as the electronic timer equipment and solution supply maybe located in any convenient place and not necessarily in the operatorscompartment. This is decidedly advantageous in the case of aircraftbecause it does not burden the pilots cabin with additional controls.

Control panel I includes a number of switches I, 8 and 9 adapted to beinserted in the respective circuits of pumping units 4, 5 and 6 forselectively cutting in or out any one of these pumping units.

In this way, it is not necessary to supply the deicing solution to allthe locations when the system is operating. Control panel I alsoincludes a selector switch In which will be more fully describedhereinafter. It functions to control the frequency of the currentimpulses of a, control circuit so as to predetermine the number ofstrokes per minute of the pumping units.

The construction of the pumping units is shown in Fig. 3. The motor foreach unit may comprise a solenoid ll suitably mounted within housing I2having end sections l3 and I4 and an intermediate section 15.Intermediate section l5 encases solenoid ll, while end section [3comprises a pressure dome having a pressure chamber I6 and inlet andoutlet valves I1 and 18. A piston 20 is disposed in a chamber 2|separated from pressure chamber l6 by a partition 22 and from thesolenoid II by a partition 23. Nipples 24 in which the valve bodies 25are threadedly disposed are carried in partition 22 and are sealed at 26to prevent the leakage of the de-icing solution from the pressurechamber H5 at this point about each nipple. Valve bodies 25 extendthrough the casing of the pressure dome and are likewise sealed at 21 toprevent leakage from pressure chamber l6. Partition 22 is attached byscrews 28 to housing l2 while the dome housing is attached to thispartition by a sealing connection 29 that prevents leaka e at thispoint.

Piston 20 of each pumping unit may comprise a spring bellows 30 whichwill return to normal 32, which may be connected to. a. pistonrod. 33;attached at its outer end to core 34 of solenoid.

When the solenoid is energized, this core.34e is drawn inwardly tocompress bellows-piston 30 and force the de-icing solution within thechamber of this piston through the passage IQ of the outlet valve body25 into the pressure chamber l6. During this time, inlet valve I1 isclosed by;-

being seated as shown in Fig. 3, and outlet valve I8 is held in theposition shown to allow the fluid to flow through, side passages 35'into pressure chamber l6 and also through outlet. passage 36. The timercontrol 2 to be hereinafter described in detail is designed to limit theflow of current through the circuit of solenoid II to the working strokeof core 34 so that when it reaches the end of this stroke, thesolenoidwill be de-energized and the spring resiliency of the bellows 30will return the bellows to its expanded position to draw on anothercharge of fiuidinto the piston chamber, and also to return the core 34to its original position. Current may befed to-the winding of solenoidII by wire31 andreturnby a grounded connection, if so desired.

Pressure chamber |6 may be allowed to retain a small amount of airtherein so that a steady stream of fluid may be fedthroughoutlet passage36 to connection 38 of the pump leading to the location where the fluidis tobe supplied to prevent frost or ice formation and to remove thesame if it has already accumulated. The design of the pumping unit issimple and; inexpensive. The unit is small, and hence, it occupies'verylittle space. It can be readily replaced byreleasing two supportingbrackets .39anddisconnecting two nipple joints at the inlet and outletconnections. Consequently, if one of the units should become disabled,it can readily be replaced, even in flight. The compactnessof the partsand .the smallnes in size permit spares to.-be carried in the tool kitfor the purpose of permitting-such ready replacement.

Actuator 40 for controlling the current flow to these solenoids of'thepumping-units-is-shown in Figs. 4 and 5. It comprises a sequence relay4| and a plurality of cams 42, 43=and 44, one for each pumping unit.Each cam isprovidedwith one or more risers 45adap-tedto=close operatingswitche 46 connected in the respective-circuits of the pumping units.Armature-41 f sequence relay 4| is preferably pivoted at 485'and itcarries a spring pawl 49 at 50. A toothed sprocket fixed to cam shaft 52so as to cause shaft 52 to rotate with the rotation of the sprocket, isarranged to turn in clockwise direction only. Opposite rotation ispreventedby-a detent spring53. As armature 41 is attracted uponenergizationof the coil of relay 4|, pawl 49 is moved to the left toturn sprocket 5| and consequently the shaft 52.- When this coil isde-energized, spring 54- will return armature 41 to its originalposition, thereby moving pawl 49 forwardly again to engage the nexttooth of sprocket 5|.

It will be noted that eachoperating'switch 46 of the pumping unitscomprises two contact springs 55 and 56, the lower contact spring 56'being provided with a button 51. As the-relay4| i energized and thepawl49-is-actuated to turn shaft 52, the riser 45 of one of the cams42*; or

44 willv engagev and lift one of the buttons 51 to close the contacts ofthe contact springs 55 and 56 of one of the operating switches 46 andthereby close the particular circuit of the pumping unit to be operated.To efiect this operation after. the operating switch 46 is closed, apower switch 66 is also closed but only for the period currentissupplied to sequence relay 4|.

Thispower. switch 60 comprises two contact springs: 6| and 62 suitablysupported upon the frame structure of relay 4| as are the operatingswitches". A- lever 63 secured to armature 41 andmovable therewith isadapted to press contact spring 62 into circuit closing position withcontact spring 6|. The power circuit is thereby closed and power issupplied to the operating switch 46 that may be closed'at the time. Thispower switch 60" may be connected in multiple with the operatingswitches 46' so that closing ofv any one of the. latter and closing thepower switch 60 will supply, current to the circuit of the pumping unitin which the closed operating switch is connected. In this connection,it will be noted that power switch 66 will be opened as soon as. thecurrent fiowthrough the coil of relay 4| ceases. This is accomplished bythe movement of armature 41 by means of spring 54 to its originalposition and the consequent movement of lever 63. to a position breakingthe circuit closing relation between thecontact springs 6| and 62,

Thetime control circuit heretofore designated as the-electronictimer 2is illustrated inFig. 2. It may comprise two vacuum tubes 66 and 66,condensers 61 and 68, resistances 69, 16 and 1|, a control relay. 12 anda selector resistor "also termed a selector. switch I0. The vacuum tubecircuit is so arranged that. when the control circult is closed,condenser 61 starts-to'draw a charging current. This, current passesthrough resist ance. 69, andthe' selector resistor; 13 biases tube 65,whichpreventscurrent from passing-therethrough. Whencondenser: 61 hasbecome nearly charged. so that its; charging; currentno longer maintainsavoltage .above. cutI-off, tube 65. begins to. pass current andcondenser- 61 discharges. This operates control relay'n-andat'. the sametime charges condenser 66';

The charging current for condenser 68- in-passing through resistance 1|biases tube 66 and-prevents-itfrompassing current. A's'condenser 66approaches-a full charge, the current drops to a point whereitno longerproduces sufficient voltage to prevent the passage of current throughtube 66; When this value is-reached, the current passing through .tube66 discharges condenser" 66 and'charges condenser 61, thusstartingthe-cycle once again.

By changing the resistance in series-with condenser 61 by means oftheselector resistor 13, which may be manually operated, the time requiredto charge this condenser 61 is varied. Since this time represents theoff time or" the time betweenstrokes of the pumping units, the number ofstrokes per minute can be controlled by changing-this resistance.Resistance. 1| controls the time thatcontrol relay 1! remains operatedand may be so. chosen, as to capacity that control relay 12" remainsenergized just long enough-to allow the'cores'34of solenoids H to make afull stroke.

It is apparentfrom Fig. 2 that controlrelay'12 may beadvantageouslyusedto, operate sequence relay 4|. Sequence relay 4|jmaybe in thepower.circuit ofthe pumping units as illustrated, but

it will be understood that a different arrangement of the parts may beprovided as long as the same result is obtained. The control relay I2 isin the timer control circuit and the period the current flows throughits coil will be controlled by resistance 1 l, and, as disclosed in thepreferred embodiment of the invention illustrated herein, thisresistance "H is selected so that it will permit the current to flowthrough the coil of the control relay 12 long enough for the pumpingunits to effect a forward working stroke. It will be observed thatresistance H may be changed to vary this period of current flow so thatpumping units of different strokes or capacities may be readily used orreplaced for those in service if a change should be desirable.

It is also possible to vary the period between the impulses of thecontrol circuit by changing the time required to charge condenser 61. Aspreviously explained, this is accomplished by manually operating theselector switch It so as to vary the resistance placed in the circuit bythis switch. Switch It! may be disposed upon panel I, and therefore, it,as well as switches l, 3 and 9, may be made readily accessible to thepilot by placing panel I in the cabin. Also, any number of pumping unitsmay be used by use of switches I, 8 and 9, and the number of strokeseach shall make per minute can be controlled from this panel I.

Actuator 40 functions to effect intermittent actuation of the pumpingunits 4, 5 and 6 although it is readily apparent that more than one unitmay operate at one time by having risers 45 on cams 42, 43 and 44differently disposed. Cam 42 is shown as provided with two risers 45 soas to effect two strokes of the pumping unit, which it controls, duringeach cycle of operation. The arrangement of the cam risers can obviouslybe changed even to the extent of having one of the pumping units incontinuous operation, while the others may operate less frequently.Using power switch 60 does not require actuation of the sequence relay4| to de-energize a pump circuit. The operating switch 46 of theparticular pump circuit energized will remain closed and not open untilthe next operation of the relay 68. This pump circuit will be brokenhowever by the opening of this power switch 60 as soon as the currentceases to flow through the relay coil on each operation. The flow ofcurrent is thus accurately controlled and is made to correspond to theperiod of the current impulses produced by the control circuit.

From the foregoing description, it will readily be observed that a novelsystem of supplying a de-icing solution to one or more locations hasbeen disclosed and that it incorporates certain novel features producingexceptional useful results in this field.

An advantage obviously resides in the fact that only one pumping unit ismade to work at a time so that the source of power will not be taxedbeyond the demand of a single pumping unit at any one time. This isimportant in the use of a deicing system when applied to moving vehiclesand particularly to airplanes, which are limited in the equipment weightthat they may carry and should not carry more batteries than may benecessary. Moreover, the parts-may be compactly arranged and simplyassembled as a complete accessory for mounting. For example, the wiringcomprising ten in number may be neatly encased in a small conduit I5leading from panel I to the electronic timer control 2, this conduit I5joining a conduit '16 containing 13 wires and continuing as conduit thepump motor to be used. If the stroke of the motor is to be increased toincrease the stroke of the pump piston, resistance H may be accordinglychanged. On the other hand, simple manipulation of resistor switch illon panel I will change the number of strokes per minute of the pumpingunits in operation. Various other features will be apparent.

Without further elaboration, the foregoing will so fully explain thegist of my invention that others may, by applying current knowledge,.readily adapt the same for use under varying conditions of service,without eliminating certain features, which may properly be said toconstitute the essential items of novelty involved, which items areintended to be defined and secured to me by the following claims.

I claim:

1. A de-icing system for aircraft, vessels, or the like, comprising aplurality of pumps adapted to be intermittently operated, mechanism foroperating said pumps, said mechanism comprising an electrically operatedactuator having means for de-energizing one pump before energizing thenext pump, an electric timing circuit for said actuator, said circuitincluding means for controlling the period of current impulses for saidactuator and means for controlling the period between said currentimpulses.

' 2. A de-icing system for aircraft, vessels, or the like, comprising aplurality of pumps adapted to be intermittently operated, mechanism foroperating said pumps, said mechanism comprising an electrically operatedactuator having means for de-energizing one pump before energizing thenext pump, an electric timing circuit for said actuator, said circuitincluding means for predetermining the duration of current impulseseffectil'lg operation of said actuator,

3. A de-icing system for aircraft, vessels, or the like, comprising aplurality of pumps adapted to be intermittently operated, mechanism foroperating said pumps, said mechanism comprising an electrically operatedactuator having means for de-energizing one pump before energizing thenext pump, an electric timing circuit for said actuator, said circuitincluding means for predetermining the frequency of current impulseseffecting operation of said actuator.

4. A de-icing systemfor aircraft, vessels, or the like, comprising aplurality of pumps adapted to be intermittently operated, mechanism foroperating said pumps, said mechanism comprising an electrically operatedactuator for said pumps, an electric timing circuit for said actuator,said circuit including a control relay for operating said actuator andmeans for controlling current impulses energizing said control relay.

5. A de-icing system for aircraft, vessels, or the like, comprising aplurality of pumps, mechanism for operating said pumps, said mechanismcomprising an electrically operated actuator for said pumps, an electrictiming circuit for said actuator, said circuit including a resistancecontrol for determining the frequency of operation of'eachipumppand-means for-selectively cutting"out :onecr more pumpswithout disabling the operation of the other pumps.

6. A de-icing system for aircrait;vessels,::or;the :likegcomprising apressure chambenforreceiv'ing :and holding a 'deicing-:solutionunderpressure, rpumpingimeansfor supplyingsaid'solution tosald chamber,mechanism for operating saidzpumping means, said mechanism comprising-anelectrically :operated actuator, an electronic timing circuit, saidcircuit including a thermionic :device with a control grid. supplyingcurrentimpulsessadapted -to effect operation of said=actuator,andmeans'in said circuit for :predetermining the durati'on o'f :eachcurrent impulse.

'7. VA de-icing system for aircraft, vesselsgor the like, comprisingaifluid-supply chamber, pumping means for supplying a de-icing solutionto-said :supply chamber, mechanism "for-operating said pumping means,said mechanism comprising an electrically operated actuator, anelectronic timing-circuit, said circuit including a thermionic "devicewith a control grid supplying current 1mpulses adaptedto effectoperation of said actuator, and means in said circuit for predeterminingYmomrimeansitoactuate -'the1period.between said current-impulses.

8. A de-icing system for=aircraft,-vessels,*or the like, comprising aplurality of electrically oper- :ated pumps,'switch means for closingthe respective circuits .of said pumps when energized, an L actuator forselectively operating :said switch .means to effect intermittent,operation of 'said pumps, a relay for operating said .actuator and atimingcircuit to energize said relay.

pumps.

14. 3A .zde-icing system f or aircraft, vessels, or*thetlike,comprisingaaplurality of-pumps-edapted to::heiintennittentlyoperated, mechanism for 0D- -er.ating1said pumps, saidmechanism comprising 315 an.a'ctuator havingmeans for -de-energiz'ingone pump before energizing the next pump, and a timingmontrolforadetermining thezperiod of op- :erationof ;each1pump and: the timeinterval be- :tween-eachzperiodoi operation.

515.11 :dea'cing systemior aircraft, vessels, or :the, like, comprisinga :plurality of pumps adapted :to bedntermittently operated,:motormeansto ac- .tuatetsaid :pumps an actuator for said motor.means,;.and:controlzmechanism for energizing said rfirstone pump andthen another-pump, said control mechanism including aartimingcontrol.forrdetermining the periodofac- :tuation :of reach; pump :andithefrequency of said :periods.

16. A de-icing system for aircraft, vessels, or the like, :comprising 'aplurality of pumps 'adapted to beiintennittently operated, anelectric'motor ;for each pump, ran electricallyoperated actuator fioriencrgizing .one .imotor before energizing the 9' A de icing sy tem-f,airc aft vesselsirorthe :next motor,-xand:an:electric circuit forenergizing like, comprising .a pluralityof electricallyoperated .pumps,:an Y operating switch for ea'ch pump, an actuator for selectivelyclosing said switches to efiect intermittent operation of said pumps, aswitch 'for controllin the power toeach operating switch, said actuatorhaving means 'to predeterminethe period of closing-of said power switchto limitthe 'flow of current to thepump-energized. .10. 'A de-icingsystem for aircraft, vessels, or athe like, comprising=a plurality 'ofelectrically operated-pumps, an operating-switch for'each pump, --a .camunit. for selectively closing said-operating switches :to inter-mittently: op era te sai'cl pumpsaan actuator for said cam-unit, anda=switch for'controlling the power to each-operating switchg and :meansTtof limitthe ffiow of: current through-said operatingrswitches and'tosaid' pumps irrespective 101 theiactiomofssaid camunit to:open'saidoperat- :ing-zswitches.

1111. :A fdesicingsystemifor aircraft, vessels, or

:-.the like, comprising a pluralityofelectrimillyop- -erated :pumps, i3,tpump :relay :assembly including -.anzoperating switch forieach pumpandaswitch for controlling thezpower to eachoperating switch, :anactuator d or ;closing; said switches, and means toilimit the; period ofclosing;ofisaidipower control switch.

12. A :de icing system for aircraft, ivessels,-:o1' the like,:comprisingza plurality of electrically op- ..erated pumps,;a;pumprelay.includingzanopera ing switch for-each plimpzanda switchxfor con--trolling the power to :each cioperatingsswitch, an actuator forclosing. said :switchesgmeanszm limit .the' period of closingofi-saidpower.controlswitch,

and :means to :control the frequency :of;saidpe- .riods of closing ofsaid powencontrol switch.

.13. .A de-icing "system for aircraft, ivessels, ior .theilike,comprising 'a plurality-of :electricallyiop- :said actuator; therebeing. means torpredetermine :therperiod: of :operation :ofsaid actuatorand the :frequencyotthe same.

17. :A :deeicin'g system :for aircraft, vessels, or

- 40 :the '1ike,:comprising1 aplurality I of pumps-adapted to beiinterm'ittently :operated, an electric motor .forceach :pump, ;a'ISCQIIEHCB- relay for r opening and .closingthe;circuits.ofzsaid-motorsand an electric timing circuit.includingactuating means therein forsaidsequence. relay and zmeansjforenergizing .said actuatingmeans ibyzcurrent impulses of pre--.determined -frequencyzand :duration.

.1 8. A ;de-;icingrsyst.em 101- aircraft, wessels, or -the like,:comprising :pumping :meansifor supplying .ade-icingsolution, .motor:means for operatingsaid-pumpingmeans, anactuator for said-m0- ztormeansga controlsrelayifor: operating said acturator, and an electronicitiming circuit for supplying current impulses to said controlrelay,-said circuit including-.means-ctogpredetermine the freouencyandduration-oiisaidicurrent impulses.

*WrAL'IIER C..: HASSELHORN.

REEERENCES CITED The following references are of record in1the 'ifileof'sthis patent:

UNITED STATES PATENTS -l\lunlber

